according to a report outlining the first-ever Dietary Reference Intakes (DRIs) recommendation intended to address chronic disease risk.
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For individuals aged 14 years and older consuming sodium above that level, cutting back could reduce their risk for hypertension and other chronic diseases, according to the report from the National Academies of Sciences, Engineering, and Medicine.
That cutoff, referred to as a Chronic Disease Risk Reduction Intake (CDRR), represents an expansion of the DRIs model beyond the Recommended Dietary Allowance (RDA) and other measures of adequacy, and the Tolerable Upper Intake Level (UL), which is the maximum intake unlikely to result in adverse health effects, a report author said in a press conference.
“CDRR is a level now that will join all the rest of the alphabet soup and be a part of how we describe recommended dietary intakes,” said Virginia A. Stallings, MD, chair of the committee that reviewed the sodium and potassium DRIs. Most U.S. adults are already consuming sodium above the recommended CDRR, said Dr. Stallings, who is a professor of pediatrics at the University of Pennsylvania, Philadelphia, and the director of the Nutrition Center at Children’s Hospital of Philadelphia.
The recommendation to reduce sodium intakes to below 2,300 mg/day applies to both hypertensive and normotensive individuals, and it could be particularly beneficial in older adults, non-Hispanic blacks, and other groups at higher risk of cardiovascular disease, Dr. Stallings and her coauthors of the new report wrote. The DRIs established in 2005 for both sodium and potassium are also updated based on new methodology in this report
Lower sodium CDRRs were set for younger individuals. Children aged 1-3 years should cut back if sodium intake is above 1,200 mg/day, while the levels for children aged 4-8 years and 9-13 years were set at 1,500 and 1,800 mg/day, respectively, according to the report.
By contrast, authors of this report were unable to establish a CDRR level for potassium based on current evidence. However, that doesn’t rule out the possibility that changing potassium intake could be beneficial, they suggested, adding that the effects of potassium need to be further explored.
Sodium and potassium play important roles in maintaining physiologic homeostasis, and they have also been implicated in risk of cardiovascular disease, mainly through their effects on blood pressure, and other chronic diseases.
“The unique nature of potassium and sodium – that is, the coexistence of their essentiality with a relationship to adverse health effects, including chronic disease risk – necessitated a new approach to the review of intake recommendations for these nutrients within the [DRI] context,” the report reads. The report also affirms, and in some cases revises, levels of sodium and potassium assumed to be adequate in healthy individuals that had been established in 2005. The sodium Adequate Intake (AI) levels for individuals aged 14-50 years is unchanged at 1,500 mg daily, but that for individuals aged 51 years and older has been increased to the 1,500-mg level.
“As we examined the evidence and looked specifically at those age cuts, there was no evidence that older people needed less sodium,” Dr. Stallings said in the press conference.
Potassium AIs were decreased for most age groups. For adults, the new recommended potassium AIs are 3,400 mg/day in men and 2,600 mg/day in women, whereas the AI for potassium was 4,700 mg/day for all adults in the 2005 recommendations.
In 2005, much of the evidence used to establish the potassium AI values was based on research studies that included potassium supplementation, rather than simply potassium intake in the usual diet. “In our process, we did not use supplementation studies, but we used the intake of apparently healthy people,” Dr. Stallings said in the press conference.
Less than half of U.S. and Canadian adults have potassium intakes that meet or exceed the potassium AI, with intakes lowest among non-Hispanic blacks, Dr. Stallings said in the press conference.
Dietary potassium intake is related to fruit and vegetable consumption, which rarely meets the recommended servings per day, Dr. Stallings and her colleagues wrote in a preface to the National Academies report. Milk, white potatoes, and fruit are higher sources of dietary potassium, she said, while coffee is the leading source of potassium for Americans aged 51 years and older.
By contrast, most sodium in the modern diet comes from commercially prepared foods and beverages, instead of consumers adding salt at the time of cooking or eating, Dr. Stallings wrote.
“For the desired public health benefit of reduced sodium intake to be achieved, more attention must be paid by industry to reducing sodium in the food supply and by consumers who have the needed sodium content information and an understanding of how to make health-inspired food choices,” they wrote in the report.
The American Heart Association’s CEO, Nancy Brown, expressed her support for the new recommendation for sodium intake. The recommendation “aligns with what the American Heart Association and other prominent public health organizations have been saying for years: We must eat less salt,” she said.
“Our excessive sodium intake isn’t entirely driven by the salt shaker; it’s largely controlled by the food industry. More than 70 percent of sodium consumed is added to food before it reaches our plates. It is added in restaurants and during the manufacturing of processed and prepackaged foods,” she claimed. “We hope this report encourages the Food and Drug Administration to quickly release its voluntary sodium reduction targets for the food industry. School leaders should also take note and reject the recent U.S. Department of Agriculture decision to weaken sodium standards in school meals and continue their commitment to serve students healthier foods.”
The DRIs report on sodium and potassium was supported by contracts between the National Academy of Sciences and the Centers for Disease Control, Food and Drug Administration, Health Canada, National Institutes of Health, Public Health Agency of Canada, and the Department of Agriculture. Partial support also came from the National Academy of Sciences W. K. Kellogg Foundation Fund and the National Academy of Medicine.
SOURCE: National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for sodium and potassium. Washington: The National Academies Press. doi: 10.17226/25353.